Nuclear Theory·nucl-th

Friday·July 24, 2015

10 papers—5 primary·5 cross-listed

01
[Submitted on 23 Jul 2015]
Entropy production in the early-cosmology pionic phase
Antonio Dobado🇪🇸 · Felipe J. Llanes-Estrada (U. Complutense Madrid)🇪🇸 · David Rodriguez-Fernandez (U. Oviedo)🇪🇸
We point out that in the early universe, for temperatures in the approximate interval 175-80 MeV (after the quark-gluon plasma), pions carried a large share of the entropy and supported the largest inhomogeneities. Thus, we examine the production of entropy in a pion gas, particularizing to inhomogeneities of the temperature, for which we benefit from the known thermal conductivity. We finally put that entropy produced in relaxing such thermal inhomogeneities in the broad context of this relatively unexplored phase of early-universe cosmology.
Comments:
10 pages, 10 figures,
Subjects:
Nuclear Theory (nucl-th); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1507.06386 [pdf]
Int.J.Mod.Phys.A(2016)·3 citations
02
[Submitted on 23 Jul 2015]
Matching the Hagedorn mass spectrum with Lattice QCD results
Pok Man Lo🇵🇱 · Michał Marczenko🇵🇱 · Krzysztof Redlich🇩🇪 · Chihiro Sasaki🇩🇪
Based on recent Lattice QCD (LQCD) results obtained at finite temperature, we discuss modeling of the hadronic phase of QCD in the framework of Hadron Resonance Gas (HRG) with discrete and continuous mass spectra. We focus on fluctuations of conserved charges, and show how a common limiting temperature can be used to constrain the Hagedorn exponential mass spectrum in different sectors of quantum number, through a matching of HRG and LQCD. For strange baryons, the extracted spectra are found to be consistent with all known and expected states listed by the Particle Data Group (PDG). The strange-mesonic sector, however, requires additional states in the intermediate mass range beyond that embodied in the database.
Comments:
8 pages, 4 figures, version to appear in phys. rev. c
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat)
arXiv:
1507.06398 [pdf]
PRC(2015)·44 citations
03
[Submitted on 23 Jul 2015]
Non-Gaussian particle number fluctuations in vicinity of the critical point for van der Waals equation of state
V. Vovchenko · R. V. Poberezhnyuk · D. V. Anchishkin · M. I. Gorenstein
The non-Gaussian measures of the particle number fluctuations -- skewness $S σ$ and kurtosis $κ σ^{2}$ -- are calculated in a vicinity of the critical point. This point corresponds to the end point of the first-order liquid-gas phase transition. The gaseous phase is characterized by the positive values of skewness while the liquid phase has negative skew. The kurtosis appears to be significantly negative at the critical density and supercritical temperatures. The skewness and kurtosis diverge at the critical point. The classical van der Waals equation of state in the grand canonical ensemble formulation is used in our studies. Neglecting effects of the quantum statistics we succeed to obtain the analytical expressions for the rich structures of the skewness and kurtosis in a wide region around the critical point. These results have universal form, i.e., they do not depend on particular values of the van der Waals parameters $a$ and $b$ . The strongly intensive measures of particle number and energy fluctuations are also considered and show singular behavior in the vicinity of the critical point.
Comments:
16 pages, 5 figures, number of figures reduced to avoid repetition, new references added, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1507.06537 [pdf]
J.Phys.A(2016)·19 citations
04
[Submitted on 23 Jul 2015]
Transient oscillations in a macroscopic effective theory of the Boltzmann equation
Dennis Bazow🇺🇸 · Mauricio Martinez🇺🇸 · Ulrich W. Heinz🇺🇸
A new transient effective theory of the relativistic Boltzmann equation is derived for locally momentum-anisotropic systems. In the expansion of the distribution function around a local "quasi-equilibrium" state a non-hydrodynamic dynamical degree of freedom is introduced at leading order that breaks local momentum isotropy. By replacing the deviation of the distribution function from this quasi-equilibrium state in terms of moments of the leading-order distribution and applying a systematic power counting scheme that orders the non-hydrodynamic modes by their microscopic time scales, a closed set of equations for the dynamical degrees of freedom is obtained. Truncating this set at the level of the slowest non-hydroynamic mode we find that it exhibits transient oscillatory behavior -- a phenomenon previously found only in strongly coupled theories, where it appears to be generic. In weakly coupled systems described by the Boltzmann equation, these transient oscillations depend on the breaking of local momentum isotropy being treated non-perturbatively at leading order in the expansion of the distribution function.
Comments:
5 pages, 1 figure; minor changes, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1507.06595 [pdf]
PRD(2016)·19 citations
05
[Submitted on 22 Jul 2015]
Fayans functional for deformed nuclei. Uranium region
S.V. Tolokonnikov · I.N. Borzov · M. Kortelainen · Yu.S. Lutostansky · E.E. Saperstein
Fayans energy density functional (EDF) FaNDF^0 has been applied to the nuclei around uranium region. Ground state characteristics of the Th, U and Pu isotopic chains, up to the two-neutron drip line, are found and compared with predictions from several Skyrme EDFs. The two-neutron drip line is found for FaNDF^0, SLy4 and SkM^* EDFs for a set of elements with even proton number, from Pb up to Fm.
Comments:
6 pages, 9 figures, to appear in the proceedings of the International Conference "Nuclear Structure and Related Topics", July 14 - July 18, 2015, Dubha, Russia
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1507.06607 [pdf]
EPJ Web Conf.(2016)·6 citations
06
[Submitted on 23 Jul 2015] (cross-list from hep-th)
Energy loss, equilibration, and thermodynamics of a baryon rich strongly coupled quark-gluon plasma
Romulo Rougemont (Sao Paulo U.)🇧🇷 · Andrej Ficnar (Oxford U., Theor. Phys.)🇬🇧 · Stefano Finazzo (Sao Paulo U. & Sao Paulo, IFT)🇧🇷 · Jorge Noronha (Sao Paulo U. & Columbia U.)🇺🇸
Lattice data for the QCD equation of state and the baryon susceptibility near the crossover phase transition (at zero baryon density) are used to determine the input parameters of a 5-dimensional Einstein-Maxwell-Dilaton holographic model that provides a consistent holographic framework to study both equilibrium and out-of-equilibrium properties of a hot and {\it baryon rich} strongly coupled quark-gluon plasma (QGP). We compare our holographic equation of state computed at nonzero baryon chemical potential, $μ_{B}$ , with recent lattice calculations and find quantitative agreement for the pressure and the speed of sound for $μ_{B} \leq 400$ MeV. This holographic model is used to obtain holographic predictions for the temperature and $μ_{B}$ dependence of the drag force and the Langevin diffusion coefficients associated with heavy quark jet propagation as well as the jet quenching parameter $q^$ and the shooting string energy loss of light quarks in the baryon dense plasma. We find that the energy loss of heavy and light quarks generally displays a nontrivial, fast-varying behavior as a function of the temperature near the crossover. Moreover, energy loss is also found to generally increase due to nonzero baryon density effects even though this strongly coupled liquid cannot be described in terms of well defined quasiparticle excitations. Furthermore, to get a glimpse of how thermalization occurs in a hot and baryon dense QGP, we study how the lowest quasinormal mode of an external massless scalar disturbance in the bulk is affected by a nonzero baryon charge. We find that the equilibration time associated with the lowest quasinormal mode decreases in a dense medium.
Comments:
51 pages, 14 figures, corrected results for the Langevin coefficients, appendix and references added. Version accepted for publication in JHEP
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.06556 [pdf]
JHEP(2016)·107 citations
07
[Submitted on 23 Jul 2015] (cross-list from hep-ph)
Forward Heavy Quarkonium Productions at the LHC
Kazuhiro Watanabe🇨🇳 · Bo-Wen Xiao🇨🇳
We investigate the low transverse momentum heavy quarkonium ( $J / ψ$ , $Υ$ ) productions in the forward rapidity region of $pp$ and $p A$ collisions at the LHC as an important probe to the transverse momentum tomography of the gluons in hadrons in the Color Glass Condensate (CGC) framework. By implementing the Sudakov resummation consistently in the CGC formalism, we achieve an excellent agreement between the improved CGC calculations and the LHC data. We show that both the small- $x$ and the Sudakov effects are essential for a complete description of heavy quarkonium productions in the low transverse momentum region. This provides a solid foundation to study the small- $x$ gluon saturation in a big nucleus with the future $p A$ programs at the LHC.
Comments:
5 pages, 3 figures; some corrections
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.06564 [pdf]
PRD(2015)·22 citations
08
[Submitted on 23 Jul 2015] (cross-list from hep-ph)
Photon production from a non-equilibrium quark-gluon plasma
Lusaka Bhattacharya🇺🇸 · Radoslaw Ryblewski🇵🇱 · Michael Strickland🇺🇸
We calculate leading-order medium photon yields from a quark-gluon plasma using (3+1)-dimensional anisotropic hydrodynamics. Non-equilibrium corrections to the photon rate are taken into account using a self-consistent modification of the particle distribution functions and the corresponding anisotropic hard-loop fermionic self-energies. We present predictions for the high-energy photon spectrum and photon elliptic flow as a function of transverse momentum, shear viscosity, and initial momentum-space anisotropy. Our findings indicate that high-energy photon production is sensitive to the assumed level of initial momentum-space anisotropy of the quark-gluon plasma. As a result, it may be possible to experimentally constrain the early-time momentum-space anisotropy of the quark-gluon plasma generated in relativistic heavy-ion collisions using high-energy photon yields.
Comments:
29 pages, 8 figures; v3 - version accepted for publication in Phys. Rev. D. arXiv admin note: text overlap with arXiv:1501.03418
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.06605 [pdf]
PRD(2016)·41 citations
09
[Submitted on 23 Jul 2015] (cross-list from hep-ph)
The resonant $π^{+} γ \to π^{+} π^{0}$ amplitude from Quantum Chromodynamics
Raul A. Briceno🇺🇸 · Jozef J. Dudek🇺🇸 · Robert G. Edwards🇺🇸 · Christian J. Shultz🇺🇸 · Christopher E. Thomas🇬🇧 · David J. Wilson🇺🇸
We present the first ab initio calculation of a radiative transition of a hadronic resonance within quantum chromodynamics (QCD). We compute the amplitude for $π π \to π γ^{⋆}$ , as a function of the energy of the $π π$ pair and the virtuality of the photon, in the kinematic regime where $π π$ couples strongly to the unstable $ρ$ resonance. This exploratory calculation is performed using a lattice discretization of QCD with quark masses corresponding to $m_{π} \approx 400$ ~MeV. We obtain a description of the energy dependence of the transition amplitude, constrained at 48 kinematic points, that we can analytically continue to the $ρ$ pole and identify from its residue the $ρ \to π γ^{⋆}$ form factor.
Comments:
V2, version accepted for publication in PRL. More references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1507.06622 [pdf]
PRL(2015)·105 citations
10
[Submitted on 23 Jul 2015] (cross-list from hep-lat)
Diagonal and off-diagonal quark number susceptibilities at high temperatures
H.-T. Ding🇨🇳 · Swagato Mukherjee🇺🇸 · H. Ohno🇺🇸 · P. Petreczky🇺🇸 · H.-P. Schadler🇺🇸
We present continuum extrapolated lattice QCD results for up to fourth-order diagonal and off-diagonal quark number susceptibilities in the high temperature region of 300-700 MeV. Lattice QCD calculations are performed using 2+1 flavors of highly improved staggered quarks with nearly physical quark masses and at four different lattice spacings. Comparisons of our results with recent weak coupling perturbative calculations yield reasonably good agreements for the entire temperature range.
Comments:
7 pages, 5 figures, RevTeX, published version, typos corrected, minor modifications
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1507.06637 [pdf]
PRD(2015)·126 citations

Affiliations

first authorsco-authorsvia INSPIRE